DE2340577A1 - DEVICE COMPOSED OF TWO PARTS JOINED BY A SHRINK SEAT - Google Patents

Description

9 P2 DT

FAGBRSTA AB «S-773 Ol FAGERSTA (SCHNEDEN) Device consisting of two means Shrink fit assembled parts

The invention relates to a device consisting of two joined together by means of a shrink fit Parts, one of which is designed as a hard metal core with a lower temperature coefficient and the other is made of steel or another material with a higher temperature coefficient.

Dies, pressing and injection tools often have one

9.Θ.1973

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Carbide core and a steel jacket. Such embedded hard metals, especially those with larger ones Hardness and service life withstand pure pressure loads very well, but can because of their great brittleness cannot withstand changing loads. It is known that the coating of hard metal cores a brings a significant increase in their resilience. Radial preload can be achieved through a shrinkage process be generated. In order to get exact dimensions of the finished part «one has to work with tight tolerances.

Another way of achieving the preload in the coated hard metal core is described in SW-PS 316 350. To form the preload, the hard metal part is surrounded by a pretensioned strip material. Possibly this technology can be compared with the so-called leather cannons used in the 30 Years War « which makes it light and at the same time resistant were made.

The well-known hatreds, however, only produce a radial bias.

It is the object of the present invention to provide a device in which it is possible, in addition to the radial Preload also to get an axial preload, so

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that forces acting radially as well as axially on the device can be absorbed without damage

The invention is achieved in that the core is calibrated against its ends tapered.

The device according to the invention shows opposite; known Devices have the advantage that they can be produced just as easily as the known devices, at the same time but can withstand larger, changing loads

The invention is based on an exemplary embodiment Explained by means of a drawing. The drawing shows one made of hard metal, preferably one made of steel shell 2 embedded core 1, for example for use as a tool for hammering of bolts. The device has a through hole 4 with a diameter d, also a Constriction 3 with a diameter d which is smaller than the diameter d. is. External loads i forces have a particularly strong effect on the constriction 3 off; any fracture that occurs becomes a fracture surface result in this area.

The external shape of the embedded, made of hard metal

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existing core 1 is chosen so that the diameter this core is greatest at a center line 5 between the two ends 6 of the core 1 and at both of its Ends 6 is smallest, the sections of the core surface in between form truncated cones

It is advantageous to have two truncated cones against each other as core 1 to arrange. It is also possible to join two cylindrical parts that form the core you can choose any combination of cylindrical and frustoconical parts, e.g. two frustoconical parts Parts and between them a cylindrical part (not shown in the drawing)

The jacket 2 cannot be created in the conventional manner, but one of the ways listed below must be followed:
the material, preferably steel, is made by either

(a) casting,

(b) forging,

(c) sintering (powder compacting) or

(d) Forms of Explosion

placed around the core to be embedded at a high temperature. During the subsequent cooling, the shrink Core 1 and the jacket 2 in the axial and radial directions.

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7340577

Both materials are chosen that the ceramic material a lower temperature coefficient than the material of the jacket. Wfgen de · higher tea temperature coefficient The jacket shrinks more than the core 1, which is made of hard metal the core 1 is stretched in the axial direction.

Accordingly desi desired amount of axial biasing of the core can be made different, that its external shape is not necessarily measured Ernest sysnetrischen double cone correspond, as is shown in the drawing. A rounded or even an asymmetrical core can also be used. In this way, depending on the intended use, a core can be created "which withstands all loading forces occurring in any direction during the""appropriate type of use.

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BATH ORIGINAL

Claims (7)

P2DT - 6 - 7340577 Expectations Device, consisting of two, by means of a shrink fit assembled parts, one of which is a hard metal core with a lower temperature coefficient and the other made of steel or another material with a higher temperature coefficient is made, characterized in that the core (1) against his Ends (6) tapered towards. 2. Apparatus according to claim 1, characterized in that the core (1) has the shape has two truncated cones placed against each other on the base surfaces. 3. Apparatus according to claim 1, characterized in that the core (1) has the shape two truncated cones placed against one another on the base surfaces as well as one or more having cylindrical parts. 4. Apparatus according to claim 3, characterized in that the core (1) consists of two truncated cones and a cylindrical cylinder arranged in between 409809/0923 BATH ORIGINAL P2 DT - 7 - 7340577 see part consists. 5. Device according to one or more of the preceding claims, characterized t that the jacket (2) consists of hot forged steel. 6 · Device according to one or more of claims 1 to 4, characterized ι that the jacket (2) is sintered warm (powder compacted). 7. Device according to one or more of claims 1 to 4, characterized * that the jacket (2) is hot explosion molded. A09809 / 0923 Blank page